The Thereminator1 is based on the TECI 67/74, sligthly modified. This schematic come from the "Popular Electronic" article published in 1967.I have replaced all transistors and fets by common european references, the TIS58 is now a BF245... It is a discrete solution. I have used two big air variable capacitors instead of usual miniatures ones.They are for coarse tuning, 2 big buttons on in the middle of the front panel. Small knobs, on each sides, are for fine tuning.

The power supply voltages is a clean +9V DC, a battery will work well too. Antenas are made with 2 bars of plain steel mounted on isolated jacks.The audio output level of the Thereminator1 is very very low ! It require a good guitar amp or a quiet mic/line preamp to drive it....Bandwidth is around 80..100Hz to more than 20kHz.

A home made module. It is a pair of VCA working as a CV crossfader/mixer between direct signal (A9) and an audio effect chain -the loop- connected between "Send" & "Return" Jacks on the front panel. The output of the mix between loop and direct sound goes directly to the Matrix ( pin13). The mix level is controled by CV coming from matrix output B9.

VCO US1 by Yves Usson as part of his original US1 synthesizer built 1979-1980 ,this VCO is based on a circuit designed by T.W. Stride (Wireless World, october 1977) ,more projects by Yves Usson http://yusynth.net/index_en.php?&arg=4

This is a modular compressor / limiter / distortion / gate unit. It was born out of my desire to have many different flavours of distortion available in a compact format. I'd had enough of my studio space being taken up by old mixing desks, battery powered guitar pedals, etc. just because I liked the sound of overdriving them. So I set about breadboarding many different designs until I found a set that gave me a good cross section of wonderful sounding distortions.

The next thing I wanted to add was a compressor or two - very useful to put before distortion in the effects chain, but I also wanted a super-flexible high fidelity unit to use stand alone as well. One nice feature is that the minimum attack rate goes so low that it makes it possible to introduce lots of self-AM distortion for bass sounds (can be a great effect, similar to a ring modulator). If the release rate is set above minimum then you don't get this effect, but instead you have an ultra fast peak limiter.

Sample and Hold by René Schmitz ,visit his pages for more details on this module and useful information on synthesizer diy http://www.uni-bonn.de/~uzs159/ from the description given on his site :

There is not much to say to this, a S&H is frequently used to create random voltages, or to sample LFOs resulting in repeating voltage patterns. When constructing this take care to deflux the board. The S&H can handle the "full" +/-10V scale. Operation is very simple, when the Gate of the FET is at -15 the FET is completely off. Thus no current can flow out of the capacitor (exept some leakage). When the Gate is turned towards +15V the FET is turned on and can charge the capacitor to the input voltage. The circuit on the right converts 5V triggers to the +/-15V triggers needed by the S&H
Jörgen Bergfors has pointed out that with a BF245A and the gate resistor R1 is altered to 47k, the circuit can reach -10V input. (Which isn't always the case in the above version.)

I'd wanted to make some sort of bit-crusher effect for ages, but never quite figured the way to use microprocessors or ADC/DACs. And then I came across the Analog Devices AD781 Sample & Hold Amp and it struck me that running this at audio rates would effectively give a simple means of changing the sampling rate - not true bit-crushing but it sounds great!

The AD781 is very easy to implement. All you need is a 5v trigger pulse at whatever rate - this must, however, be of very narrow pulses, so I used a 40106 chip (with 5v supply) to make a narrow pulse osc. You also need to keep the pulses narrow to avoid signal bleed through. From this point I added a Voltage Controlled Resistor onto the circuit to make the Trigger Osc voltage controllable. These circuits were designed for my modular system - they run off a +/- 12v bipolar supply

The 1st circuit is the simple stand-alone - simple & very effective. The 2nd circuit adds voltage control to the 1st circuit (along with some tweaks for the particular application). An LM13700 is used for a floating VC Resistor (resistor values found by trial & error!) and this is driven by a log converter based on a Ray Wilson Music From Outer Space schematic.

The module is built around an LF398 Sample and Hold chip.
The rising edge of the clock- / trigger signal (0V => 5V) triggers a 4098 monoflop which sends a 10µs 5V pulse to the sample control input of the LF398 which stores the input signal voltage in a hold capacitor during this time. After termination of the sample pulse the signal voltage value is kept by the capacitor.
The output of the LF398 is given to a pair of opamps for each signal path. On one signal path the first opamp works as an inverting amplifier, on the other signal path it is a non inverting one. According to the 'Glide' switch position the output voltage passes a portamento circuit (pot plus capacity) or is connected directly to the output buffer stage (2nd opamp of the signal path).
As I wanted to display the current glide selection optically I used a double switch for glide activation. The other swich is used to switch on the control LED.
To let the 4098 start in a defined behaviour I implemented a chip reset of one second (1m resistor and 1µ capacity).

Buchla 146 Sequential Voltage Source by Don Buchla ,described at the Buchla historical site as : Produces a sequence of two to sixteen programmed voltages at each of three outputs. Otherwise identical to Model 123.

A 2 foot long piece of 1 1/2 inch diameter wooden dowel was mounted horizontally on the top of an old lamp stand with some angle brackets and wood screws. Along the top of this dowel a length of 1/2 inch mylar adhesive tape was applied. Then graphite powder (the type for lock and key lubrication) was rubbed into the mylar tape until the total resistance from end to end was about 100K ohms. Next, a belt was trimmed to the same length as the dowel. Then a 1/2 inch wide strip of brass shimstock was glued down along the center of one side of the belt. The belt was then attached to the top of the dowel at either end with washers underneath, so that it was suspended over top of the mylar/graphite tape with the brass strip facing down. Electrical connections were made using ring lugs on one side of the assembly.

Next, a basic sample and hold was built for the controller using a FET and a few op amps. The circuit is similar to that which Eric Barbour uses for his keyboard controllers, with a few mods and additions. The electronics was installed in a nifty little plastic box and attached it to the stand just under the ribbon controller. It has three controls; pitch, which offsets the CV output; width, which increases or decreases the CV output range; and glide, which is a basic portamento. There is one LED for power and another to indicate triggering (bright flash) and key down (dimmer steady light). As the whole circuit is just running on a single 15 volt supply, CV output range is from about 1 to 14 volts, which works well with my tube oscillators but which could also be adapted to solid state oscillators if required

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